1. Field of the Invention
This invention relates to a linear electric generator of the type disclosed in parent U.S. patent application Ser. No. 10/170,715, and more particularly to a linear electric generator that includes one or both of the following:                Armature magnets or multiple pole stationary magnet structures having a series of N-S alternating poles and constructed using a novel joining method that overcomes problems of high remanance and coercivity, and thereby increases flux density;        Stationary or movable windings constructed using a novel winding method that results in maximum magnetic line cutting during linear motion.        
2. Description of Related Art
In a linear electric generator, the magnetic elements and windings are in linearly reciprocal motion relative to each other. This linear reciprocal motion causes a diamagnetic effect that resists the motion of the magnetic elements within the windings, reducing the electromotive force.
Typically, the moving part of the generator is an armature consisting of a single magnet arranged to move linearly through a coil. To counter the losses caused by the diamagnetic effect, it was proposed in copending U.S. patent application Ser. No. 10/170,715, filed Jun. 14, 2002, to use multiple windings and magnetic elements, and to add accelerating elements to the generator. The accelerating elements may be in the form of resilient elements, such as rubber plugs or metal springs situated at the ends of travel of the moving magnets to impart a mechanical rebounding force as the magnets engage the resilient elements and reverse direction, in the form of a magnetic material or system that generates a repulsive force as the moving magnets approach the end of their travel, or in the form of a combination of mechanical and magnetic elements.
Such linear generators are compact and efficient, and can be used to convert motion of the generator into a source of recharging power for a variety of electronic devices, such as cellular telephones (which are the subject of copending U.S. patent application Ser. No. 10/170,717), personal CD players, handheld electronic game players, and the like. This eliminates the need to obtain charging power from the electrical power grid, saving energy and reducing pollution associated with electricity generation, and also promotes the use of rechargeable batteries, reducing environment hazards associated with disposable non-rechargeable batteries.
A limitation on the commercial development of such power sources has been the relatively low magnetic efficiency of suitable sized and priced magnets and coils, which typically have a relatively low flux density and/or provide an inefficient distribution of magnetic lines. Although more efficient magnets or magnet/coil structures are known, such as the rare earth magnets disclosed in U.S. Pat. Nos. 5,347,186 and 5,818,132; the composite armature and multiple coil structure of U.S. Pat. No. 4,500,827; the wound magnetic core disclosed in U.S. Pat. No. 4,709,176; or the composite coil and stack- neodymium disc magnets disclosed in U.S. Pat. No. 5,975,714, the previously proposed magnet and/or coil structures are generally expensive to manufacture and/or too large for the applications mentioned above. Further, while distribution of magnetic lines from a coil can be improved by adding a permeable material to the coil structure, the permeable material has the disadvantage not only of adding to the complexity of the structure, but also to the diamagnetic resistance effect.